Evaluate
-\frac{2b-a}{a+2b}
Expand
-\frac{2b-a}{a+2b}
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\frac{a\left(a+2b\right)}{\left(a+2b\right)^{2}}+\frac{2b}{a-2b}-\frac{4ab}{a^{2}-4b^{2}}
Factor the expressions that are not already factored in \frac{a^{2}+2ab}{a^{2}+4ab+4b^{2}}.
\frac{a}{a+2b}+\frac{2b}{a-2b}-\frac{4ab}{a^{2}-4b^{2}}
Cancel out a+2b in both numerator and denominator.
\frac{a\left(a-2b\right)}{\left(a-2b\right)\left(a+2b\right)}+\frac{2b\left(a+2b\right)}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{a^{2}-4b^{2}}
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of a+2b and a-2b is \left(a-2b\right)\left(a+2b\right). Multiply \frac{a}{a+2b} times \frac{a-2b}{a-2b}. Multiply \frac{2b}{a-2b} times \frac{a+2b}{a+2b}.
\frac{a\left(a-2b\right)+2b\left(a+2b\right)}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{a^{2}-4b^{2}}
Since \frac{a\left(a-2b\right)}{\left(a-2b\right)\left(a+2b\right)} and \frac{2b\left(a+2b\right)}{\left(a-2b\right)\left(a+2b\right)} have the same denominator, add them by adding their numerators.
\frac{a^{2}-2ab+2ba+4b^{2}}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{a^{2}-4b^{2}}
Do the multiplications in a\left(a-2b\right)+2b\left(a+2b\right).
\frac{a^{2}+4b^{2}}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{a^{2}-4b^{2}}
Combine like terms in a^{2}-2ab+2ba+4b^{2}.
\frac{a^{2}+4b^{2}}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{\left(a-2b\right)\left(a+2b\right)}
Factor a^{2}-4b^{2}.
\frac{a^{2}+4b^{2}-4ab}{\left(a-2b\right)\left(a+2b\right)}
Since \frac{a^{2}+4b^{2}}{\left(a-2b\right)\left(a+2b\right)} and \frac{4ab}{\left(a-2b\right)\left(a+2b\right)} have the same denominator, subtract them by subtracting their numerators.
\frac{\left(a-2b\right)^{2}}{\left(a-2b\right)\left(a+2b\right)}
Factor the expressions that are not already factored in \frac{a^{2}+4b^{2}-4ab}{\left(a-2b\right)\left(a+2b\right)}.
\frac{a-2b}{a+2b}
Cancel out a-2b in both numerator and denominator.
\frac{a\left(a+2b\right)}{\left(a+2b\right)^{2}}+\frac{2b}{a-2b}-\frac{4ab}{a^{2}-4b^{2}}
Factor the expressions that are not already factored in \frac{a^{2}+2ab}{a^{2}+4ab+4b^{2}}.
\frac{a}{a+2b}+\frac{2b}{a-2b}-\frac{4ab}{a^{2}-4b^{2}}
Cancel out a+2b in both numerator and denominator.
\frac{a\left(a-2b\right)}{\left(a-2b\right)\left(a+2b\right)}+\frac{2b\left(a+2b\right)}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{a^{2}-4b^{2}}
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of a+2b and a-2b is \left(a-2b\right)\left(a+2b\right). Multiply \frac{a}{a+2b} times \frac{a-2b}{a-2b}. Multiply \frac{2b}{a-2b} times \frac{a+2b}{a+2b}.
\frac{a\left(a-2b\right)+2b\left(a+2b\right)}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{a^{2}-4b^{2}}
Since \frac{a\left(a-2b\right)}{\left(a-2b\right)\left(a+2b\right)} and \frac{2b\left(a+2b\right)}{\left(a-2b\right)\left(a+2b\right)} have the same denominator, add them by adding their numerators.
\frac{a^{2}-2ab+2ba+4b^{2}}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{a^{2}-4b^{2}}
Do the multiplications in a\left(a-2b\right)+2b\left(a+2b\right).
\frac{a^{2}+4b^{2}}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{a^{2}-4b^{2}}
Combine like terms in a^{2}-2ab+2ba+4b^{2}.
\frac{a^{2}+4b^{2}}{\left(a-2b\right)\left(a+2b\right)}-\frac{4ab}{\left(a-2b\right)\left(a+2b\right)}
Factor a^{2}-4b^{2}.
\frac{a^{2}+4b^{2}-4ab}{\left(a-2b\right)\left(a+2b\right)}
Since \frac{a^{2}+4b^{2}}{\left(a-2b\right)\left(a+2b\right)} and \frac{4ab}{\left(a-2b\right)\left(a+2b\right)} have the same denominator, subtract them by subtracting their numerators.
\frac{\left(a-2b\right)^{2}}{\left(a-2b\right)\left(a+2b\right)}
Factor the expressions that are not already factored in \frac{a^{2}+4b^{2}-4ab}{\left(a-2b\right)\left(a+2b\right)}.
\frac{a-2b}{a+2b}
Cancel out a-2b in both numerator and denominator.
Examples
Quadratic equation
{ x } ^ { 2 } - 4 x - 5 = 0
Trigonometry
4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}